Interphone on Acoustic Neuroma:
Increased Risk Among Heavy Users
The Interphone results on acoustic neuroma (AN) are —finally— out. As in the Interphone analysis of brain tumors, there does appear to be a higher risk among the heaviest users of cell phones. Yet, as before, the results are uncertain and open to alternative explanations.
Here is the closing paragraph of the paper in Cancer Epidemiology:
"In conclusion, we did not observe an increase in risk of AN with ever [sic] regular use of a mobile phone or in mobile phone users who began use 10 years or more before the reference date. Further, we did not see any trend in AN risk with increasing cumulative use; the lowest [odds ratio] OR was in the 9th decile of cumulative call time. There was an increased odds ratio for those with heavy (1640 h or more) cumulative call time, particularly in long-term users and in those who reported use of a mobile phone on the same side of their head as the tumor occurred. This increase could be due to chance, reporting bias or a causal effect. It is possible too that the interval between introduction of mobile phones and occurrence of the tumor we studied was too short to observe an effect, if there is one, as acoustic neuroma is usually a slowly growing tumor."
The paper was made available to the IARC panel in May before its public release. In a summary statement, issued after the meeting, IARC reported that the decision to classify wireless radiation as a "possible human carcinogen" was based, in part, on these results.
Once again as in virually all the Interphone risk estimates, the majority of the odds ratios in the acoustic neuroma paper are less than one, suggesting some type of systematic bias. In an appendix to the brain tumor paper, published last year, a method was presented to compensate for that bias, yielding some provocative results pointing to a more consistent risk. That analysis was hidden away on the Internet. For acoustic neuroma, a similar, secondary analysis was also carried out, though this time with less dramatic effect. It also appears in an appendix, but as part of the published paper.